Process for forming a microfiche

ABSTRACT

A microfiche is formed by coating a transparent support sheet with a layer of transparent potentially adhesive thermoplastic composition exhibiting low adhesive tackiness at ambient conditions, but which is heat-activatable to adhesive tackiness, positioning microfilm image elements on the layer under a sufficient pressure to superficially adhere the elements to the layer, and bringing the thermoplastic composition to adhesive tackiness in the areas of the microfilm elements. Reheating the thermoplastic composition in the areas of the microfilm elements renders the elements removable from the sheet, thus providing for replacement of microfilm elements to revise or update the microfiche.

United States Patent Merk et al. Feb. 29, 1972 [54] PROCESS FOR FORMINGA 3,165,848 1/1965 Langan ..40/158 MICROFICHE 3,383,264 5/1968 Welch....156/247 3,130,099 4/1964 Homburger... ..l56/57 [721 Inventors FmMerk, Wwsbaden; Gerhard Deb, 2,835,620 5/1958 Bartlett ...,l56/333 xAismannshausem Herbert Ewald Muller, 3,036,977 5/1962 KOCh etal............l56/332X Wwsbaden, all of Germany 3,275,589 9/1966 Alexander etal.... ....156/332 x Assigneez Kalle wiesbaden et al. X

Blebnch Germany Primary Examiner--Carl D. Quarforth [22] Filed: Nov. 24,1969 Assistant Examiner-E. A. Miller Attorney-J. Russell Juten, Peter F.Willig, Lionel N. White [21] Appl' 879017 and Milford A. Juten [30]Foreign Application Priority Data ABSTRACT Nov, 27, 1968 Germany ..P 1811 212.4 A microfiche is formed y coating a transparent pp sheet with alayer of transparent potentially adhesive thermoplastic 52 us. c1..l56/247, 156/299, 156/332, composition exhibiting low adhesivetackiness at ambient 9011- 5 33 56/344,161 3 161/406 ditions, but whichis heat-activatable to adhesive tackiness, 51 1111. c1 ..B32b 7/06 Pmicrofilm image elements the layer under a {58] Field 'ofSearch..235/61.12; 156/247, 299, 332, ficiem Pressure superficially adhere theelements 156/333, 344 layer, and bringing the thermoplastic compositionto adhesive tackiness in the areas of the microfilm elements. Reheating[56] References Cited the thermoplastic composition in the areas of themicrofilm elements renders the elements removable from the sheet, thusUNITED ES PATENTS providing for replacement of microfilm elements torevise or update the microfiche. 3,253,360 5/1966 Spicer ..40/1583,083,132 3/1963 Miehle ..l56/234 6 Claims, 3 Drawing FiguresPATENTEUFEB29 I972 3,645,823

I N VEN TORS.'

FRITZ MERK GERHARD DEBLIS BY HERBERT E. MULLER mam ATTORNEY PROCESS FORFORMING A MICROFICIIE BACKGROUND OF THE INVENTION For bettercard-indexing and organization, it is known to make microfilm images ofdocuments, drawings, and written information on sheet films havingapproximately the size on file cards or to copy them from film strips.Utilizing as much as possible of the light-sensitive surface of thesheet microfilm, individual documents, for example, are copiedside-by-side and line-by-line in consecutive steps onto the sheetmicrofilm. The process has the disadvantage that it always requires arelatively slowly working step and repeat camera. Another known methodconsists in that the arrangement of the documents in the fonn of stripson the sheet microfilm is achieved by lineby-linecopying of rollfilmstrips onto light-sensitive material. The two mentioned casesrequirerelatively slowing working optical devices, and furthermore, themicrofiches do not allow subsequent changes or insertions.

In order to overcome these disadvantages, it has been suggested to keepstrips of microfilm images in correspondingly measured transparent bagswhich can be sorted in the form of a card index. The individual stripscan easily be replaced by others or, if desired, supplemented. For thepreparations of reenlargements or duplicates of the microfilm images, itis either necessary to take the film strip out of the bag every time orto expose it through the bag. In the latter case, a loss of sharpness isunavoidable. Another disadvantage of this process resides in that thebags can contain only strips of a limited width.

According to another known process, the film strips are bonded onto atransparent film support by means of an adhesive. The process iscomparatively complicated and usually requires a special device forcovering the backside of the film with an adhesive, for cutting the filminto suitable strips, and for bonding these strips in the desiredposition onto a transparent support. According to this process, only themarginal portions of the film are coated with the adhesive so that thecentral parts of the image are not always plane when being pressed ontothe reproduction material during the preparation of further copies. Thisresults in a lack of sharpness, of course. Changes or insertions in themounted card are not readily possible since the hardened bonded assemblygenerally cannot be separated without damaging the support or the bondedfilm. The remaining adhesive residues impair the transparency andinterfere with the application of the new microfilm image.

It has been found that the above disadvantages can be overcome in asimple manner by employing a new mounting process and a new mountingfilm for microfilm images.

SUMMARY The present invention provides a process for mounting microfilmelements onto a transparent support, thereby forming a microfiche, whichcomprises coating the surface of the support entirely or partially witha thermoplastic layer which is only slightly adhesive at ambienttemperature, but is heatactivatable to adhesive tackiness, laying themicrofilm image element or elements .onto the desired area of thesupport, preferably with the back of the element in contact with thethermoplastic layer, pressing the elements in position, and brieflyheating the thermoplastic layer in the area occupied by the microfilmelements.

According to an embodiment of the process, the microfilm images and thesupport are heated only to such an extent that they can be separatedagain after cooling without being damaged.

The present invention further provides a mounting film for theperformance of the proce$ of the invention which consists of adimensionally stable transparent support with a thin coating ofthermoplastic substance which is adhesive in the heat in a temperaturerange in which the dimensional stability of the support issubstantiallymaintained.

The thermoplastic layer preferably is so selected that it superficiallyadheres to a microfilm element at normal temperature under pressure.

DRAWING FIG. 2 shows a microfiche assembly comprising mounting I film l0bearing microfilm strips 14 and a microimage of another size 15 mountedonto'the thermoplastic layer. The

unused surface of the mounting film may be covered at a later date withfurther microfilm elements. The upper margin of the film has a legibletext 16 with sorting characteristics.

FIG. 3 is a cross section of the microfiche showing a microfilm element15 comprising the film base 18 and the image layer 19 adhered to supportsheet 11 by means of thermoplastic adhesive layer 12.

DESCRIPTION By means of the process of the invention, it is possible bysimple means to mount microfilm images of different number and size ontoa support. For mounting, the microfilm image to be fastened is laid ontothe desired place of the support, compressed therewith and heated.Heating may be performed in the simplest way under a heated platen, forexample. It is also advantageous to pass the mounting film with themicrofilm image thereon between two heated rollers. It is particularlyadvantageous when the thennoplastic layer of the mounting film, asmentioned above, adheres slightly to the film support at normaltemperature and pressure. By means of this often undesirable phenomenonknown in technology as blocking." it is possible to fasten the filmimage by slightly pressing it to such an extent that it can no longerslide on the surface of the mounting film. The simultaneous mounting ofseveral images or strips is thus considerably facilitated because thesheet microfilm card superficially mounted in this manner can be passedthrough a heated pair of rollers, for example, without the risk of adisplacement of the images.

When using the mounting film in countries with a high normal temperatureor when it is intended to print it or to provide it with sortingperforations, it may be advantageous, however, to select an adhesivewhich begins to adhere to the film only at higher temperatures, e.g.,above 50 C.

The sheet microfilm mounted in accordance with the invention can besupplemented at any time by adding further images in the above-describedmanner. A change, i.e., a replacement of images by others, is alsopossible but care should be taken that bonding with the thermoplasticlayer is performed at a temperature at which the assembly becomes not sofirm that it cannot be separated again after cooling without damagingthe film or the support. The bonding temperature depends on the natureof the thermoplastic layer used and and be determined by simple tests.In the case of the usual thermoplastic adhesives suitable for the use inaccordance with the invention, bonds are generally made attemperaturesin a range from about 40 to 70 C., which can easily be separated againby pulling the film image and the support apart. When making a permanentbond, bonding preferably is performed at higher temperatures the upperlimit of which is determined by the decomposition temperature of thefilm layer or the softening or deformation temperature of the mountingfilm. Although it is usually not necessary, it is possible, for example,to briefly heat without danger images on silver halide or diazo film totemperatures from to C. For the desired bond, temperatures of 100 C. orbelow generally are entirely sufficientwith the usual heat-activatableadhesives. The bond achieved therewith is very firm and stable. Ifrequired, it can only be separated again after previous heating of themounted assembly to a suitable temperature.

The microfiches obtained according to the mounting process of theinvention can be used for the preparation of duplicates andreenlargements in the usual manner. Since the image layer preferably isoutside, the reproduction procedure is not connected with a loss ofsharpness. For protecting the image layer, the microfiches may be keptin transparent bags and then be sorted in the form of a card index.

In addition to the microfilm images, there may be mounted text parts,sorting marks and the like on the support, which are legible withoutmagnification and facilitate card-indexing and sorting.

The microfilm images to be mounted may be originals (e.g., on silverhalide film) or duplicates (e.g., on diazo film). The bases of thesefilm materials generally consist of cellulose acetate, nowadayssometimes also of polyester or other plastics. All such materials caneasily be mounted according to the process of the invention. Althoughmounting with the layer outside is preferable, it is also possible tomount films having the layer inside. This may be the case with very thinbases without considerable sharpness losses occurring during thepreparation of further copies. When no further copies are to be madethis mounting method may even be of particular advantage.

As in the case of the known sheet microfilms, the base of the mountingfilm consists of a transparent dimensionally stable flexible material.Plastics films, e.g., of cellulose acetate or other cellulose esters,polyesters, polycarbonates, and the like are suitable for this purpose.When using films of synthetic plastics materials with a lowadhesiveness, e.g., of polyethylene terephthalate, a known pretreatmentfor increasing the surface adhesion is advantageous.

The base of the mounting film may be coated entirely or partially with alayer of a known thermoplastic adhesive. Suitable heat-activatableadhesives are, for example, polyvinyl acetate, vinyl acetate copolymers,acrylic acid ester homopolymers and copolymers, polybutenes and styrene,and the like, natural resins, such as mastic, copal, etc. Adhesives witha suitable melting range are particularly obtained in known manner bymixing such constituents with one another and with other additives, suchas plasticizers, silicone resins, polyethylene, coumarone indene resins,pentaerythrite ester resins, etc. Vinyl acetate homopolymers andcopolymers, e.g., maleic acid alkyl esters, acrylic acid ester, and thelike, in the form of solutions or dispersions have proved particularlysuitable.

Partial coating of the support with thermoplastic adhesive may beperformed in such a manner, for example, that a portion is left uncoatedat the upper margin of the support and, instead, is so treated that, forexample, indications or sorting characteristics allowing mechanicalsorting can be written or printed thereon.

Coating with an adhesive may also be performed in the form of strips orin certain patterns so that the film strip is bonded only at the marginsor, for certain purposes, only spotwise.

For avoiding adhesion of the mounting films to one another.

during storage in large stacks over a relatively long time, thethermoplastic layer may also be covered with a thin cover film or anappropriately treated paper, e.g., silicone paper, which is removedbefore mounting. It is also possible to coat the back side of themounting film with an antiadhesive layer, e.g., ofpolytetrafluoroethylene. The cover film may also be printed, forexample, with lines or squares and, during mounting, be placed under thefilm as an orientation auxiliary.

PREFERRED EMBODIMENTS Example 1 An approximately 0.2 mm. thick celluloseacetate film was coated on one side with a thin layer of anapproximately 50 percent aqueous dispersion of a copolymer from about 60percent of vinyl acetate and 40 percent of dibutyl maleate, whichcontained about 1 percent of anionic and nonionic wetting agents asstabilizer, and the coating was dried. The film was highly transparentand, on the coated surface, smooth and no more tacky. The coated filmwas cut to sizes of I05 X 148 mm. Two strips 14 of a 16 mm. microfilmwere laid with the backside downward onto the desired place of such afilm card 10, as shown in FIG. 2, and provisionally fastened by slightlypressing them by hand. The film strips were safe from displacement anddid not separateby themselves during handling of the card. A strip oftransparent paper was typewritten with numbers and signs serving forclassifying the contents of the microfilm photos and the written strip16 was inserted at the upper margin of the mounting card. The assemblywas then heated for some seconds to about 50 C. by means of a flatiron.After cooling, the film strips firmly adhered to the card and did notseparate even when being bended to and fro. But the film strips could beseparated at the comers with the fingernail and then be pulled down fromthe support without being damaged.

In another test, the mounted assembly was heated to about C. instead ofheating it to 50 C. For protecting thefilm gelatin layer, a glass fiberfabriccoated with polytetrafluoroethylene was placed between the filmand the heated surface. The achieved bond was so firm that it could notbe separated without damaging the film or the thermoplastic layer.

Similar results were achieved when, for coating the' support, a mixturewas used consisting of 70 parts by weight of a 53 percent aqueousdispersion of a copolymer of vinyl acetate and butyl acrylate and 30parts by weight of a 52 percent aqueous polyvinyl acetate dispersionwhich contained 10 percent of plasticizer, calculated on the polyvinylacetate.

For storage, the obtained microfiches were put into transparent filmbags and sorted in filing boxes. For the preparation of duplicates, thecard was placed with the layer side of the film onto the light-sensitivelayer of the reproduction material and exposed to light. Duplicates ofthe sharpness of the original were obtained.

Example 2 A cellulose acetate film as that of Example 1 was coated witha thin layer of a solution of the following composition and dried:

'25 parts by weight of a copolymer from 86 percent of vinyl chloride, 13percent of vinyl acetate, and about 1 percent of an unsaturateddicarboxylic acid,

25 parts by weight of methyl ethyl ketone,

10 parts by weight of ethyl acetate 10 parts by weight of butyl acetate,

30 parts by weight of toluene,

25 parts by weight of hydrogenated methyl abietate (Heb colyn D,registered trademark of Hercules Incorporated, USA) As in Example 1,microfilm strips were sealed at 50 C. onto suitable pieces of the coatedmounting film. The micro-images could be separated again from themounting film without damage. In a reenlargement device, very sharpenlargements of the mounted microfilm images were obtained.

The above examples have been presented for the purpose of illustrationand should notbe taken to limit the scope of the present invention. Itwill be apparent that the described examples are capable of manyvariations and modifications which are likewise to be included withinthe scope of the present invention as set forth in the appended claims.

What is claimed is:

1. A process for forming a microfiche of a plurality of microfilmelements which comprises:

a. providing a transparent sheet having coated thereon oversubstantially the whole of its surface a layer consisting essentially ofa transparent potentially adhesive thermoplastic composition exhibitinga low initial adhesive tackiness at ambient temperature, but activatableto substantial adhesive tackiness at a temperature above about 50 C;

b. ambient temperature in contact with said thermoplastic compositionlayer and under sufficient pressure to superficially adhere saidelements to said layer; and

c. heating said thermoplastic composition layer in areas contacted bysaid microfilm elements to a temperature between about 50 C. and thedeformation temperature of said elements, thereby effecting substantialadhesive bonding between said sheet and said elements by virtue of theheat-activated tackiness of said thermoplastic composition.

2. The process according to claim 1 wherein said thermoplasticcomposition consists essentially of a blend of about equal parts of a86:l3:1 copolymer of vinyl chloride: vinyl acetate: unsaturateddicarboxylic acid, and hydrogenated methyl abietate.

3. The process according to claim 1 wherein said thermoplasticcomposition consists essentially of a 60:40 copolymer of vinyl acetate:dibutyl maleate.

4. The process according to claim 1 wherein said therassembling saidplurality of microfilm elements at saidb. removing said selected elementfrom said microfiche thermoplastic composition layer while saidcomposition is in said heated condition.

6. A process according to claim 5 which additionally comprises replacingthe thus removed microfilm element with a different microfilm elementand reheating said thermoplastic composition to within said temperaturerange, thereby bonding said different element to the microfiche sheet.

2. The process according to claim 1 wherein said thermoplastic composition consists essentially of a blend of about equal parts of a 86:13:1 copolymer of vinyl chloride: vinyl acetate: unsaturated dicarboxylic acid, and hydrogenated methyl abietate.
 3. The process according to claim 1 wherein said thermoplastic composition consists essentially of a 60:40 copolymer of vinyl acetate: dibutyl maleate.
 4. The process according to claim 1 wherein said thermoplastic composition consists essentially of a mixture of about 37 parts of a copolymer of vinyl acetate: butyl acrylate, about 15 parts of polyvinyl acetate, and about 2 parts of a polyvinyl acetate plasticizer.
 5. A process of revising or updating a microfiche prepared according to the process of claim 1 which comprises: a. heating the thermoplastic composition of said microfiche in the area occupied by a selected microfilm element to a temperature between about 50* C. and the deformation temperature of said element; and b. removing said selected element from said microfiche thermoplastic composition layer while said composition is in said heated condition.
 6. A process according to claim 5 which additionally comprises replacing the thus removed microfilm element with a different microfilm element and reheating said thermoplastic composition to within said temperature range, thereby bonding said different element to the microfiche sheet. 